Abstract

Buffering is indispensable in packet-switching systems. Optical frequency-division multiplexing (FDM) techniques make it possible to design a compact buffer fabric.¹ A transparent optical-loop buffer is one of the simplest buffering schemes; the packet storage time corresponds to the number of circulations in a loop-connected optical fiber.^2,3 The storage time in an optical-loop buffer is theoretically unlimited, but the number of circulations is actually limited because an optical-loop buffer must have optica] amplifiers to compensate for the optical power loss of the packets circulating through the fiber loop. Amplified spontaneous emissions are generated by the amplifiers, degrading the signal-to-noise ratio. The amplitude of the signal varies with the wavelength and/or polarizaion, causing power fluctuations in the output packets. This limitation can be overcome by using our proposed differential receiver,⁴ which can receive 10-dB power-fluctuated packets, instead of a conventional receiver.

© 1996 Optical Society of America